1. Field of the Invention
The present invention relates to an image processing apparatus for performing processing on image data on which security is provided, and so on.
2. Description of the Related Art
Copiers have recently attained widespread use for producing duplicates of a document in offices of business, offices of public organizations, and homes.
The spread of copiers enables people to make a copy easily. However, the prevalence of copiers may cause undesirable effects such as leakage of duplicates of confidential documents, and misuse of duplicates of the original documents.
To cope with this, there have been proposed various approaches for enhancing the security of a copier.
One of such approaches is as follows. During a print process of a document, a specific pattern called a background pattern or the like is printed in the background of the document. Then, when the document having the background pattern is read in a copier, producing an output such as printing is restricted.
For example, the technique has been proposed in which, when image information of an original read by a reading means is printed out, a password is added to the image information that is a confidential document (Japanese Laid-open Patent Publication No. 2003-316552).
The following technique has also been proposed. A background pattern embedded in the background of an image obtained by an image obtaining means is extracted. When the extracted background pattern coincides with a predetermined pattern, an image is prohibited from being outputted by an image output means unless a user is verified based on his/her user ID and password entered by him/her (Japanese Laid-open Patent Publication No. 2004-201069).
Another technique has been proposed in which background patterns added to a plurality of regions contained in one page of a document are detected; and a user is requested to enter a password depending on the detected background pattern (Japanese Laid-open Patent Publication No. 2008-118215). This technique increases flexibility in security.
Another technique has also been proposed in which the security of an image forming apparatus is ensured and the use efficiency of hardware resources of the image forming apparatus is improved (Japanese Laid-open Patent Publication No. 2009-160846).
As described above, it has been suggested that a copier is equipped with the following function: when a document to which background patterns are added for each page of the document or for each region contained therein is read, a duplicate of the document is not outputted unless a user is verified based on a password entered by him/her, and the like. The function is sometimes called, for example, a password-protected copy function.
Such a password-protected copy function equipped in a copier restricts the use thereof. Specifically, making a copy of highly-confidential documents and the like is restricted. This improves the security of the copier; however, sometimes reduces the usability of the copier for users.
To be specific, when using the copier equipped with the password-protected copy function, a user is required to enter a password or the like every time a background pattern is detected in a document before outputting all the pages of the document, which sometimes bothers the user.
For example, when the user intends to make a copy of a document containing a plurality of pages to each of which a different background pattern is added, he/she is required to enter a password or the like every time one page is outputted.